Did they make you a promise? It doesn't sound like it from the way you described it; it sounded more like an expression of opinion as to what might happen. But then, I wasn't there.

Personally, I wouldn't be holding my breath, even if they did actually promise to credit you Avios and TPs provided you gave AA your BAEC number. As I said, it's a scenario that is not unknown (ie non-partner code, oneworld operator), and it seems quite clear that that does not normally earn Avios / TPs.